> I installed the newest version und the error is gone, but we have instead a new one: "f.divHover is undefined"
Like with divShadow we didn't change anything.
The Scheduler object is initialized and rendered during the "mounted" phase (it requires the underlying placeholder element to be rendered first). Before "mounted" phase is reach, this.$refs.scheduler returns undefined.
You are trying to load the events in the "created" phase and to overcome this problem (accessing this.scheduler causes "Cannot read property 'control' of undefined" error) you have created another instance of DayPilot.Scheduler manually somewhere (and it uses the same placeholder). When accessing this.scheduler later you are working with an instance which is not linked to the placeholder correctly and it is throwing errors.
> I replaced .init() with .update(), but the results are the same.
In your "loadTimeline" method, you set the date using "startdate" which is incorrect - you need to use "startDate" (note the case).
You also try to generate the timeline manually using "timeline" property but that only works if you set scale="Manual". See also:
https://doc.daypilot.org/scheduler/timeline/
You can download a sample Vue.js Scheduler project here:
https://code.daypilot.org/46517/vue-js-scheduler-changing-visible-date
It includes the correct initialization logic and it demonstrates the options you have when changing the Scheduler properties.
Let me know if the problems persist.